Add util/ratelimit.pl to assist with choosing ratelimit settings.
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447d236c 1$Cambridge: exim/src/README.UPDATING,v 1.7 2005/04/28 13:06:32 ph10 Exp $
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2
3This document contains detailed information about incompatibilities that might
4be encountered when upgrading from one release of Exim to another. The
5information is in reverse order of release numbers. Mostly these are relatively
6small points, and the configuration file is normally upwards compatible, but
7there have been two big upheavals...
8
9
10**************************************************************************
11* There was a big reworking of the way mail routing works for release *
12* 4.00. Previously used "directors" were abolished, and all routing is *
13* now done by routers. Policy controls for incoming mail are now done by *
14* Access Control Lists instead of separate options. All this means that *
15* pre-4.00 configuration files have to be massively converted. If you *
16* are coming from a 3.xx release, please read the document in the file *
17* doc/Exim4.upgrade, and allow some time to complete the upgrade. *
18* *
19* There was a big reworking of the way domain/host/net/address lists are *
20* handled at release 3.00. If you are coming from a pre-3.00 release, it *
21* might be easier to start again from a default configuration. Otherwise *
22* you need to read doc/Exim3.upgrade and do a double conversion of your *
23* configuration file. *
24**************************************************************************
25
26
27The rest of this document contains information about changes in 4.xx releases
28that might affect a running system.
29
30
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31Version 4.51
32------------
33
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341. The format in which GnuTLS parameters are cached (in the file gnutls-params
35in the spool directory) has been changed. The new format can also be generated
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36externally, so it is now possible to update the values from outside Exim. This
37has been implemented in an upwards, BUT NOT downwards, compatible manner.
38Upgrading should be seamless: when Exim finds that it cannot understand an
39existing cache file, it generates new parameters and writes them to the cache
40in the new format. If, however, you downgrade from 4.51 to a previous release,
41you MUST delete the gnutls-params file in the spool directory, because the
42older Exim will not recognize the new format.
43
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442. When doing a callout as part of verifying an address, Exim was not paying
45attention to any local part prefix or suffix that was matched by the router
46that accepted the address. It now behaves in the same way as it does for
47delivery: the affixes are removed from the local part unless
48rcpt_include_affixes is set on the transport. If you have a configuration that
49uses prefixes or suffixes on addresses that could be used for callouts, and you
50want the affixes to be retained, you must make sure that rcpt_include_affixes
51is set on the transport.
52
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533. Bounce and delay warning messages no longer contain details of delivery
54errors, except for explicit messages (e.g. generated by :fail:) and SMTP
55responses from remote hosts.
56
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58Version 4.50
59------------
60
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61The exicyclog script has been updated to use three-digit numbers in rotated log
62files if the maximum number to keep is greater than 99. If you are already
63keeping more than 99, there will be an incompatible change when you upgrade.
64You will probably want to rename your old log files to the new form before
c3af992c 65running the new exicyclog.
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66
67
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68Version 4.42
69------------
70
71RFC 3848 specifies standard names for the "with" phrase in Received: header
72lines when AUTH and/or TLS are in use. This is the "received protocol"
73field. Exim used to use "asmtp" for authenticated SMTP, without any
74indication (in the protocol name) for TLS use. Now it follows the RFC and
75uses "esmtpa" if the connection is authenticated, "esmtps" if it is
76encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
77appear in log lines as well as in Received: header lines.
78
79
80Version 4.34
81------------
82
83Change 4.31/2 gave problems to data ACLs and local_scan() functions that
84expected to see a Received: header. I have changed to yet another scheme. The
85Received: header is now generated after the body is received, but before the
86ACL or local_scan() is called. After they have run, the timestamp in the
87Received: header is updated.
88
89Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
90which is lucky, since I decided it was a bug fix.
91
92
93Version 4.33
94------------
95
96If an expansion in a condition on a "warn" statement fails because a lookup
97defers, the "warn" statement is abandoned, and the next ACL statement is
98processed. Previously this caused the whole ACL to be aborted.
99
100
101Version 4.32
102------------
103
104Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
105verification now uses <> in the MAIL command by default, as it did before. A
106new callout option, "use_sender", has been added to request the other
107behaviour.
108
109
110Version 4.31
111------------
112
1131. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
114 or greater. The interface to the obsolete 0.8.x releases is no longer
115 supported. There is one externally visible change: the format for the
116 display of Distinguished Names now uses commas as a separator rather than a
117 slash. This is to comply with RFC 2253.
118
1192. When a message is received, the Received: header line is now generated when
120 reception is complete, instead of at the start of reception. For messages
121 that take a long time to come in, this changes the meaning of the timestamp.
122 There are several side-effects of this change:
123
124 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
125 the logged header lines no longer include the local Received: line,
126 because it has not yet been created. If the message is a non-SMTP one,
127 and the error is processed by sending a message to the sender, the copy
128 of the original message that is returned does not have an added
129 Received: line.
130
131 (b) When a filter file is tested using -bf, no additional Received: header
132 is added to the test message. After some thought, I decided that this
133 is a bug fix.
134
135 The contents of $received_for are not affected by this change. This
136 variable still contains the single recipient of a message, copied after
137 addresses have been rewritten, but before local_scan() is run.
138
1392. Recipient callout verification, like sender verification, was using <> in
140 the MAIL FROM command. This isn't really the right thing, since the actual
141 sender may affect whether the remote host accepts the recipient or not. I
142 have changed it to use the actual sender in the callout; this means that
143 the cache record is now keyed on a recipient/sender pair, not just the
144 recipient address. There doesn't seem to be a real danger of callout loops,
145 since a callout by the remote host to check the sender would use <>.
146
147
148Version 4.30
149------------
150
1511. I have abolished timeout_DNS as an error that can be detected in retry
152 rules, because it has never worked. Despite the fact that it has been
153 documented since at least release 1.62, there was no code to support it.
154 If you have used it in your retry rules, you will now get a warning message
155 to the log and panic log. It is now treated as plain "timeout".
156
1572. After discussion on the mailing list, Exim no longer adds From:, Date:, or
158 Message-Id: header lines to messages that do not originate locally, that is,
159 messages that have an associated sending host address.
160
1613. When looking up a host name from an IP address, Exim now tries the DNS
162 first, and only if that fails does it use gethostbyaddr() (or equivalent).
163 This change was made because on some OS, not all the names are given for
164 addresses with multiple PTR records via the gethostbyaddr() interface. The
165 order of lookup can be changed by setting host_lookup_order.
166
167
168Version 4.23
169------------
170
1711. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
172 that cannot be overridden. The default in the distributed EDITME is "root".
173 If for some reason you were (against advice) running deliveries as root, you
174 will have to ensure that FIXED_NEVER_USERS is not set in your
175 Local/Makefile.
176
1772. The ${quote: operator now quotes an empty string, which it did not before.
178
1793. Version 4.23 saves the contents of the ACL variables with the message, so
180 that they can be used later. If one of these variables contains a newline,
181 there will be a newline character in the spool that will not be interpreted
182 correctely by a previous version of Exim. (Exim ignores keyed spool file
183 items that it doesn't understand - precisely for this kind of problem - but
184 it expects them all to be on one line.)
185
186 So the bottom line is: if you have newlines in your ACL variables, you
187 cannot retreat from 4.23.
188
189
190Version 4.21
191------------
192
1931. The idea of the "warn" ACL verb is that it adds a header or writes to the
194 log only when "message" or "log_message" are set. However, if one of the
195 conditions was an address verification, or a call to a nested ACL, the
196 messages generated by the underlying test were being passed through. This
197 no longer happens. The underlying message is available in $acl_verify_
198 message for both "message" and "log_message" expansions, so it can be
199 passed through if needed.
200
2012. The way that the $h_ (and $header_) expansions work has been changed by the
202 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
203 until release 4.30, then the manual) for full details. Briefly, there are
204 now three forms:
205
206 $rh_xxx: and $rheader_xxx: give the original content of the header
207 line(s), with no processing at all.
208
209 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
210 then decode base64 or quoted-printable "words" within the header text,
211 but do not do charset translation.
212
213 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
214 standard character set.
215
216 If you have previously been using $h_ expansions to access the raw
217 characters, you should change to $rh_ instead.
218
2193. When Exim creates an RFC 2047 encoded word in a header line, it labels it
220 with the default character set from the headers_charset option instead of
221 always using iso-8859-1.
222
2234. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
224 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
225 called TMPDIR, and if it finds it is different, it changes its value.
226
2275. Following a discussion on the list, the rules by which Exim recognises line
228 endings on incoming messages have been changed. The -dropcr and drop_cr
229 options are now no-ops, retained only for backwards compatibility. The
230 following line terminators are recognized: LF CRLF CR. However, special
231 processing applies to CR:
232
233 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
234 nor a local message in the state where . is a terminator.
235
236 (ii) If a bare CR is encountered in a header line, an extra space is added
237 after the line terminator so as not to end the header. The reasoning
238 behind this is that bare CRs in header lines are most likely either
239 to be mistakes, or people trying to play silly games.
240
2416. The code for using daemon_smtp_port, local_interfaces, and the -oX options
242 has been reorganized. It is supposed to be backwards compatible, but it is
243 mentioned here just in case I've screwed up.
244
245
246
247Version 4.20
248------------
249
2501. I have tidied and re-organized the code that uses alarm() for imposing time
251 limits on various things. It shouldn't affect anything, but if you notice
252 processes getting stuck, it may be that I've broken something.
253
2542. The "arguments" log selector now also logs the current working directory
255 when Exim is called.
256
2573. An incompatible change has been made to the appendfile transport. This
258 affects the case when it is used for file deliveries that are set up by
259 .forward and filter files. Previously, any settings of the "file" or
260 "directory" options were ignored. It is hoped that, like the address_file
261 transport in the default configuration, these options were never in fact set
262 on such transports, because they were of no use.
263
264 Now, if either of these options is set, it is used. The path that is passed
265 by the router is in $address_file (this is not new), so it can be used as
266 part of a longer path, or modified in any other way that expansion permits.
267
268 If neither "file" nor "directory" is set, the behaviour is unchanged.
269
2704. Related to the above: in a filter, if a "save" command specifies a non-
271 absolute path, the value of $home/ is pre-pended. This no longer happens if
272 $home is unset or is set to an empty string.
273
2745. Multiple file deliveries from a filter or .forward file can never be
275 batched; the value of batch_max on the transport is ignored for file
276 deliveries. I'm assuming that nobody ever actually set batch_max on the
277 address_file transport - it would have had odd effects previously.
278
2796. DESTDIR is the more common variable that ROOT for use when installing
280 software under a different root filing system. The Exim install script now
281 recognizes DESTDIR first; if it is not set, ROOT is used.
282
2837. If DESTDIR is set when installing Exim, it no longer prepends its value to
284 the path of the system aliases file that appears in the default
285 configuration (when a default configuration is installed). If an aliases
286 file is actually created, its name *does* use the prefix.
287
288
289Version 4.14
290------------
291
2921. The default for the maximum number of unknown SMTP commands that Exim will
293accept before dropping a connection has been reduced from 5 to 3. However, you
294can now change the value by setting smtp_max_unknown_commands.
295
2962. The ${quote: operator has been changed so that it turns newline and carriage
297return characters into \n and \r, respectively.
298
2993. The file names used for maildir messages now include the microsecond time
300fraction as well as the time in seconds, to cope with systems where the process
301id can be re-used within the same second. The format is now
302
303 <time>.H<microsec>P<pid>.<host>
304
305This should be a compatible change, but is noted here just in case.
306
3074. The rules for creating message ids have changed, to cope with systems where
308the process id can be re-used within the same second. The format, however, is
309unchanged, so this should not cause any problems, except as noted in the next
310item.
311
3125. The maximum value for localhost_number has been reduced from 255 to 16, in
313order to implement the new message id rules. For operating systems that have
314case-insensitive file systems (Cygwin and Darwin), the limit is 10.
315
3166. verify = header_syntax was allowing unqualified addresses in all cases. Now
317it allows them only for locally generated messages and from hosts that match
318sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
319
3207. For reasons lost in the mists of time, when a pipe transport was run, the
321environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
322form used in Message-ID: header lines). The 'E' has been removed.
323
324
325Version 4.11
326------------
327
3281. The handling of lines in the configuration file has changed. Previously,
329macro expansion was applied to logical lines, after continuations had been
330joined on. This meant that it could not be used in .include lines, which are
331handled as physical rather than logical lines. Macro expansion is now done on
332physical lines rather than logical lines. This means there are two
333incompatibilities:
334
335 (a) A macro that expands to # to turn a line into a comment now applies only
336 to the physical line where it appears. Previously, it would have caused
337 any following continuations also to be ignored.
338
339 (b) A macro name can no longer be split over the boundary between a line and
340 its continuation. Actually, this is more of a bug fix. :-)
341
3422. The -D command line option must now all be within one command line item.
343This makes it possible to use -D to set a macro to the empty string by commands
344such as
345
346 exim -DABC ...
347 exim -DABC= ...
348
349Previously, these items would have moved on to the next item on the command
350line. To include spaces in a macro definition item, quotes must be used, in
351which case you can also have spaces after -D and surrounding the equals. For
352example:
353
354 exim '-D ABC = something' ...
355
3563. The way that addresses that redirect to themselves are handled has been
357changed, in order to fix an obscure bug. This should not cause any problems
358except in the case of wanting to go back from a 4.11 (or later) release to an
359earlier release. If there are undelivered messages on the spool that contain
360addresses which redirect to themselves, and the redirected addresses have
361already been delivered, you might get a duplicate delivery if you revert to an
362earlier Exim.
363
3644. The default way of looking up IP addresses for hosts in the manualroute and
365queryprogram routers has been changed. If "byname" or "bydns" is explicitly
366specified, there is no change, but if no method is specified, Exim now behaves
367as follows:
368
369 First, a DNS lookup is done. If this yields anything other than
370 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
371 getipnodebyname() (or gethostbyname() on older systems) and the result of the
372 lookup is the result of that call.
373
374This change has been made because it has been discovered that on some systems,
375if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
376returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
377first, and only if that gives a definite "no such host" to try the local
378function.
379
3805. In fixing the minor security problem with pid_file_path, I have removed some
381backwards-compatible (undocumented) code which was present to ease conversion
382from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
383contain "%s", which was replaced by the port number for daemons listening on
384non-standard ports. In Exim 4, such daemons do not write a pid file. The
385backwards compatibility feature was to replace "%s" by nothing if it occurred
386in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
387the problem by removing the backwards compatibility feature. Thus, if you still
388have "%s" somewhere in a setting of pid_file_path, you should remove it.
389
3906. There has been an extension to lsearch files. The keys in these files may
391now be quoted in order to allow for whitespace and colons in them. This means
392that if you were previously using keys that began with a doublequote, you will
393now have to wrap them with extra quotes and escape the internal quotes. The
394possibility that anybody is actually doing this seems extremely remote, but it
395is documented just in case.
396
397
398Version 4.10
399------------
400
401The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
402to better reflect its function. The OS-specific files have been updated. Only
403if you have explicitly set this in your Makefile (highly unlikely) do you need
404to change anything.
405
406****